Last Sunday, while the eyes of the world were on the brouhaha that had followed the killing of 1,400 Syrians with poison gas, rather less attention was paid to an incident in neighbouring Iraq, where hundreds of Iraqi and Iranian troops burst into the remains of the once-neat little desert town of Ashraf to murder 52 unarmed Iranian dissidents in cold blood – many of them were handcuffed and shot in the back of the head.

One reason we might be concerned by this tragedy, however, is that this massacre, carried out on the direct orders of Iran’s Supreme Leader, the Ayatollah Khamenei, was only the latest twist to a much longer story, which arguably makes our own Foreign Office a passive accessory to the crime. I have long been reporting here on the extraordinary drama of how the residents of Ashraf have been horribly betrayed, not just by the prime minister of Iraq, Nouri al-Maliki, but also by a man called Martin Kobler, who until recently was the personal representative in Iraq of the UN secretary-general Ban Ki-moon.

No sooner had the last US forces left Iraq in 2009, having given each Ashraf resident a personal guarantee of safety, than the tragedy, engineered by their enemies in Tehran, began to unfold. In a first assault on Ashraf, 47 were killed and hundreds injured.

Then, in 2011, Kobler tricked 2,000 Ashrafites into moving, under false pretences, to a former US base, Camp Liberty, which turned out to be no more than a squalid prison, where scores more have been killed or injured.

Last weekend, deliberately taking advantage of the international focus on Syria, Iran’s Supreme Leader – Assad’s chief backer in the region – gave orders for another murderous assault on Ashraf, organised by Qassem Suleimani, commander of Iran’s Quds force, which is responsible for acts of terror across the Middle East. As Qassem reported in Tehran two days later, in a speech in which he said “we support Syria to the end”, the latest Ashraf operation had been a great success. Throughout this awful story neither the British Foreign Office nor the US State Department has raised a cheep of protest at the amply documented part played in it by Mr Kobler.

When I asked the Foreign Office about this last February, after the latest assault on liberty had left seven people dead, it would only say that it “fully supported” everything Kobler had done in Iraq. There is clearly much more going on here than our government is prepared to tell us.